Hiemstra B.,University of Groningen |
Mendez M.,University of Groningen |
Done C.,Durham University |
Trigo M.D.,Newton Science Operation Center |
And 2 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2011
We observed the new X-ray transient and black hole candidate XTEJ1652-453 simultaneously with XMM-Newton and the Rossi X-ray Timing Explorer (RXTE). The observation was done during the decay of the 2009 outburst, when XTEJ1652-453 was in the hard-intermediate state. The spectrum shows a strong and broad Fe emission line with an equivalent width of ∼450 eV. The profile is consistent with that of a line being produced by reflection off the accretion disc, broadened by relativistic effects close to the black hole. The best-fitting inner radius of the accretion disc is ∼4 gravitational radii. Assuming that the accretion disc is truncated at the radius of the innermost stable circular orbit, the black hole in XTEJ1652-453 has a spin parameter of ∼0.5. The power spectrum of the RXTE observation has an additional variability component above 50 Hz, which is typical for the hard-intermediate state. No coherent quasi-periodic oscillations at low frequency are apparent in the power spectrum, which may imply that we view the system at a rather low inclination angle. © 2010 The Authors Monthly Notices of the Royal Astronomical Society © 2010 RAS.
Coffey D.,Newton Science Operation Center |
Coffey D.,Trinity College Dublin |
Longinotti A.L.,Newton Science Operation Center |
Longinotti A.L.,Massachusetts Institute of Technology |
And 9 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2014
In this work, the analysis of multi-epoch (1995-2010) X-ray observations of the Seyfert 1 galaxy H0557-385 is presented. The wealth of data presented in this analysis show that the source exhibits dramatic spectral variability, from a typical unabsorbed Seyfert 1 type spectrum to a Compton-thin absorbed state, on time-scales of ~5 yr. This extreme change in spectral shape can be attributed to variations in the column density and covering fraction of a neutral absorbing medium attenuating the emission from the central continuum source. Evidence for Compton reflection of the intrinsic nuclear emission is present in each of the spectra, though this feature is most prominent in the low-state spectra, where the associated Fe emission line complex is clearly visible. In addition to the variable absorbing medium, a warm absorber component has been detected in each spectral state. Optical spectroscopy concurrent with the 2010 XMM-Newton observation campaign has detected the presence of broad optical emission lines during an X-ray absorption event. From the analysis of both X-ray and optical spectroscopic data, it has been inferred that the X-ray spectral variability is a result of obscuration of the central emission region by a clumpy absorber covering ≥ 80 per cent of the source with an average column density of NH ~ 7 × 1023 cm-2, and which is located outside the broad line region at a distance from the central source consistent with the dust sublimation radius of the AGN. © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.
Cardaci M.V.,Autonomous University of Madrid |
Cardaci M.V.,National University of La Plata |
Hagele G.F.,Autonomous University of Madrid |
Hagele G.F.,National University of La Plata |
And 4 more authors.
Proceedings of the International Astronomical Union | Year: 2010
We present a detailed analysis of all the X-ray data taken by the XMM-Newton satellite of a small sample of five Seyfert 1 galaxies: ESO 359-G19, HE 1143-1810, CTS A08.12, Mkn 110, and UGC 11763. Our aim is to characterize the different components of the material that print the absorption and emission features in the X-ray spectra of these objects. The continuum emission was studied through the EPIC spectra taking advantage of the spectral range of these cameras. The high resolution RGS spectra were analyzed in order to characterize the absorbing features and the emission line features that arise in the spectra of these sources. © 2011 International Astronomical Union.
Antonucci M.,University of Rome Tor Vergata |
Talavera A.,Newton Science Operation Center |
Vagnetti F.,University of Rome Tor Vergata |
Trevese D.,University of Rome La Sapienza |
And 5 more authors.
Astronomy and Astrophysics | Year: 2015
Context. The XMM-Newton X-ray observatory has repeatedly observed the Chandra Deep Field-South (CDF-S) in 33 epochs (2001-2010) through the XMM-CDFS Deep Survey. During the X-ray observations, XMM-OM targeted the central 17 × 17 arcmin2 region of the X-ray field of view, providing simultaneous optical/UV coverage of the CDF-S. The resulting set of data can be used to build an XMM-OM catalogue of the CDF-S, filling the UV spectral coverage between the optical surveys and GALEX observations. Aims. We present the UV catalogue of the XMM-CDFS Deep Survey. Its main purpose is to provide complementary UV average photometric measurements of known optical/UV sources in the CDF-S, taking advantage of the unique characteristics of the survey (UV and X-ray simultaneous data, time monitoring ∼8.5 years, multi-wavelength photometry). The data reduction is also intended to improve the standard source detection on individual observations by cataloguing faint sources by stacking their exposure images. Methods. We re-processed the XMM-OM data of the survey and stacked the exposures from consecutive observations using the standard Science Analysis System (SAS) tools to process the data obtained during single observations. Average measurements of detections with SAS good quality flags from individual observations and from stacked images were joined to compile the catalogue. Sources were validated through the cross-identification within the ESO Imaging survey (Arnouts et al. 2001) and the COMBO-17 survey (Wolf et al. 2004). Results. Photometric data of 1129 CDF-S sources are provided in the catalogue, and optical/UV/X-ray photometric and spectroscopic information from other surveys are also included. The stacking extends the detection limits by ∼1 mag in the three UV bands, contributing ∼30% of the catalogued UV sources. The comparison with the available measurements in similar spectral bands confirms the validity of the XMM-OM calibration. The combined COMBO-17/X-ray classification of the "intermediate" sources (e.g. optically diluted and/or X-ray absorbed AGN) is also discussed. © ESO 2015.
Ballo L.,Institute Fisica Of Cantabria Csic Uc |
Piconcelli E.,National institute for astrophysics |
Vignali C.,University of Bologna |
Schartel N.,Newton Science Operation Center
Monthly Notices of the Royal Astronomical Society | Year: 2011
We report the first high-energy detection of PG 1700+518, a well-known low-ionization broad absorption line quasar (quasi-stellar object, QSO). Due to previous X-ray non-detection, it was classified as soft X-ray weak QSO. We observed PG 1700+518 with XMM-Newton for about 60ks divided in three exposures. The spectrum below 2keV is very steep, Γ∼ 2.4-3.8, while at higher energies the extremely flat emission (photon index Γ∼ 0.15, when modelled with a power law) suggests the presence of strong absorption (NH, pl∼ 2 × 1023cm-2, Γ fixed to 1.8) or a reflection-dominated continuum. The broad-band flux is consistent with previous non-detection. Simultaneous European Photon Imaging Camera (EPIC) and Optical Monitor (OM) data confirm its X-ray weakness (observedαox∼-2.2). The level of obscuration derived from the X-ray spectra of PG 1700+518 cannot explain its soft X-ray nuclear weakness unless a column density of NH≳ 2 × 1024cm-2 is present. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.